Generator regulator



July 25, 1944. w. J. RADY GENERATOR REGULATOR Filed Aug. 24, 1942 2 Sheets-Sheet 1 M; My

July 25, 1944. w J RADY GENERATOR REGULATOR Filed Aug. 24, 1942 2 Sheets-Sheet 2 Patented July 25, 1944 GENERATOR REGULATOR William J. Rady, Anderson, Ind., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application August 24, 1942, Serial No. 455,893

2 Claims.

This invention relates to regulators for controlling the output of a generator.

An object of the invention is to provide a carbon pile regulator which will be the least sensitive to variations in environment temperature.

A further object is to provide a voltage regulator of rugged and compact construction having an operating electromagnet of relatively large size thereby rendering the regulator more sensitive to variations in voltage or current output from the generator, depending on whether the instrument is used as a voltage responsive regulator or as a current responsive regulator.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a side view of a carbon pile regulator constructed in accordance with the present invention.

Figs. 2 and 3 are end views taken respectively in the direction of the arrows 2 and 3 of Fig. 1.

Fig. 4 is a sectional view on the line 4-4 of Fig. 1.

Fig. 5 is a wiring diagram of the regulator.

Fig. 6 is a plan view of the regulator base with certain parts mounted thereon.

Fig. 7 is a sectional view on the line of Fig. 4.

Referring to Fig. 3, it will be seen that a base 20 supports the feet 2| (attached by screws 22 to the base 20) of a frame 23 (Fig. 4) having an annular flange 24 and ears 25 through which screws 26 extend. Screws 26 extend also through ears 2! rovided by a magnetizable plate 28 and through ears 28 provided by a magnetizable plate 30, through the cars 25 of frame 23 and through tubes 3| and screw threadedly engage ears 32 of a plate 33 integral with a carbon pile housing 34 having heat radiating fins 35. As shown in Fig. 2 the plate 33 is attached by screws 36 to arms 31 integral with the base 20. The plates 28, 36, 33 and the frame 23 are somewhat similar in contour. When the screws 26 are tightened the parts 28, 38, 23 and 3| are clamped between the head of these screws and the ears 32 of the plate 33.

Referring to Fig. 2, a triangular shaped plate 40 is attached by screws 4| to the plate 33 and is insulated therefrom by insulating plate 42, insulating bushing 43'(Fig. 4) and insulating washer 44. Plate 40 has a boss 45 threadedly engaged by screw 46 to a metal disc 41 to which a carbon contact disc 48 is attached. The screw 46 is turned to adjust initially the contact pressure between the carbon discs 50 located in a non-conducting tube 5| of refractory material, such as porcelain. Tube 5| is retained by a ring 5|a attached to housing 33 by screws 5|b. The screw 46 is retained in adjusted position by the tightening of a screw 52 (Fig. 1) which forces a part 53 of the boss 45 toward the main part of the boss from which the part 53 is separated by a saw cut 54. A screw 55 secures a terminal clip 56 to boss 45.

The frame 23 houses a cupped compensator ring 66 of bi-metal against which the radially extending fingers 6| of the discs 62 of resilient metal are urged in the direction toward the right in Fig. 4. The compensator ring 66 compensates for variations in the resistance of the magnet windings 91 and 98 due to changes in the temperature of these windings. The discs 62 are separated by spacers 63, but the ends of fingers 6| of these discs engage each other and the finger nearest the compensator disc engages it. The drawings show four of the discs 62, but the number of these discs may vary according to the requirements. The discs 52 and the spacer 63 are confined between insulating discs 64 and65 and these discs and spacers are secured to a magnetizable armature 68 by screws 61 and 88. Screw 68 secures to the armature 63 a metal bracket 18 which is insulated by the disc 65 and bushing H and by washer 12 through which the screws 68 pass. Bracket 10 has an arm 14 for receiving a screw 15 by which a wire terminal 16 is attached to the arm 14.

The bracket 10 is secured to a brass tube attached to a metal disc 8| carrying a carbon disc 82 for engaging the right end of the carbon pile 50.

As stated before, the screw 46 is turned for the purpose of placing the carbon pile discs 50 under a certain pressure required to give a predetermined resistance which is in the field circuit F of a generator G, as shown in Fig. 5. It is important that this resistance should not be affected by changes in environment temperature. The pressure between the carbon discs 56 is initially that exerted by the fingers 6| against the compensator 60. Elongation and contraction of screws 26 cause variation in the distance between the frame 23 at the right of the compensator 60 and the plate 33 at the left end of the carbon disc housing 34. Therefore, variations in the length of screws 26 would tend to change the pressure exerted by the fingers 6| against the compensator 60 and the pressure of that member against the frame 23 and hence to vary the resistance of the carbon pile. Compensation for this change is effected by the brass tube ll which, though shorter than the screw 26 made of steel, has a greater co-eificient of expansion. The elongation and contraction of tube 80 is substantially equal to the elongation and contraction of screws 28 thereby maintaining the initial resistance of carbon pile 50 substantially uniform for variations in environment temperature. The heat radiating housing 34, made preferably of aluminum, may expand and contract without affecting the resistance of the carbon pile since this housing is supported at the left end only by its mounting plate 33. There is sufficient resiliency in the arms 31 of the base 20 to allow for any changes in distance between frame 23 and plate 33 due to changes in length of the screws 28 and of the tubes 21 which are also made of steel.

The electromagnet, designated generally by II, which controls the movement of the armature i6 is of generous proportions. The electromagnet comprises a magnetizable cup made of formed steel to which a thick ring 02 is riveted to provide an adequate flux path to a relatively large magnetizable core 03 screw threadedly engaging the parts SI and U2. The core 93 is provided with a screw driver slot "a so that the core can be turned by a screw driver to adjust the air gap between the core and the armature. Screws 9! pass through washers 94 and threadedly engage the ring 92 to hold the core 93 in the desired position of adjustment. The cup Ii encloses an actuating magnet coil l1 and a compensating coil 0! mounted upon a brass spool 99 supported by the core $3. One pole of the electromagnet is provided by the left end of core 03 and the other pole of annular formation is provided by the magnetizable plate 30. The central hole in plate I is defined by beveled surface I" terminating in a sharp annular edge Ill into which the flux attempts to crowd and is consequently diverted into the space between the armature II and the core 83. The frame 23 being constructed preferably of aluminum and therefore non-magnetizable carries no flux. It merely serves as a member to which the end plates II of the electromagnet SI are clamped by the screws 20.

According to Figs. 5 and 6, the regulator has terminals, marked I to 8 respectively, arranged as shown. Carbon pile 50 is connected with terminals l and 2. Actuating coil 91 is connected with terminal 2 and with a variable resistor Ill and with a fixed resistance Illl connected with terminal 3. Terminals 2 and 3 are connected respectively with the positive and negative terminals of the generator G. Terminal i is connected with field F. The generator G is connected with the battery B throughout a cut-out relay CR. Winding 91 which is responsive to generator voltage, as shown in the diagram, controls the position of armature 66. When the voltage tends to increase beyond a certain value the armature 66 moves to the right to decrease the pressure between the discs of the carbon pile 50, thus increasing the field resistance to reduce the field excitation and the generator voltage. The voltage responsive coil 91 may be replaced by a current responsive coil connected in series between the generator and the battery. As shown in my copending application, Serial No. 470,959 filed Jan. 1, 1943 (invention DR-7850), the field cir-v cult I" may be controlled by two carbon pile regulators of similar construction in which the carbon piles are connected together in series with th field 1'. One regulator is responsive to generator voltage and the other to current output.

The compensator coil 1. is used where a plurality of generators are connected with the same storage battery. In such cases each generator is provided at least with a voltage regulator. One end of each compensating coil is connected with the negative brush of its associated generator and the other ends of all the compensating coils II are connected to a common wire. In this way all of the compensating coils OI are affected by the voltage of all of the generators in such a way that if one generator tends toward overvoltage the compensating coil of the regulator of the over-voltage generator will be excited more than the other compensating coils so that the field resistance of the over-voltage generator will be additionally increased to reduce the voltage of that generator.

The fixed resistance H0 is used so as to make it possible to lower the resistance of the coil II thereby reducing the amount of compensation that is required to take care of the variations in resistance in coil ll due to variations in temperature therein. By reducing the amount of compensation that is required, it is possible to keep the size of the compensator ll within reasonable limits. The variable resistance III is used to vary the voltage at which the regulator will begin to regulate. The fixed resistance III is contained in a box I secured to the base 2. by screws I ll passing through ears ill provided by the box H2 and cooperating with nuts ill. The variable resistance III is contained in a box ll. attached to a plate Ill, attached by screws I", to ears Ill integral with base 1|. Resistance III is controlled by a handle or knob I the position of which is yieldingly maintained by a detent l2i on a leaf spring II! which engages the knurled periphery of knob III.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A carbon pile regulator comprising juxtaposed carbon discs forming a stack or pile, a housing enclosing the pile, an electrode engaging one end of the pile and fixed relative to one end of the housing, an electrode engaging the other end of the pile and movable relative to the other end of the housing, a frame located adjacent to the last mentioned end of the housing, means extending alongside the housing for securing the frame to the remote first mentioned end of the housing in spaced relation thereto, an electromagnet supported by the frame, an armature cooperating with the electromagnet and attached to the movable electrode, resilient means operatively connected with the frame and with the armature for urging the armature toward the pile, and a member for transmitting motion from the resilient means to the movable electrode adjacent thereto, said member being made of material having such greater temperature coeilicient of expansion than that of the material of the means which secures the frame to the first mentioned end of the housing that the elongation of said member compensates for elongation of said securing means.

2. A carbon pile regulator comprising juxtaposed carbon discs forming a stack or pile, a housing enclosing the pile and having one end relatively fixed and the other end free oi. obstruction to elongation or contraction due to temperature change, an electrode iixed to the fixed end oi. the housing and engaging one end of the pile, an electrode engaging the other end 0! the pile and movable relative to the free end of the housing, a frame located adjacent to the free end 0! the housing, elongated elements extending alongside the housing for securing the frame to the remote fixed end of the housing in spaced relation thereto, an electromagnet supported by the frame, an armature cooperating with the electromagnet and attached to the movable electrode, resilient means operatively connected with the frame and with the armature tor urging the armature toward the pile, and a member for transmitting motion from the resilient means to the movable electrode adiacent thereto, said member being made of material having such greater temperature coemcient of expansion than that oi the material oi. the elongated elements that the elongation of said member compensates for the elongation oi said elements.

WILLIAM J. RADY. 

